A mother of one of six children killed in a primary school jumping castle tragedy has lashed out at a company operator accused of workplace safety breaches.

Chace Harrison, Jalailah Jayne-Maree Jones, Zane Mellor, Addison Stewart, Jye Sheehan and Peter Dodt were killed when an inflatable castle was lifted into the air in December 2021. Three children were also seriously injured.

They were enjoying end-of-year celebrations with classmates on the oval of Hillcrest Primary School at Devonport in Tasmania’s northwest.

Rosemary Anne Gamble, the owner of Taz-Zorb which supplied and set up the castle, was charged in November with failing to comply with workplace health and safety requirements.

Gamble appeared in Devonport Magistrates Court on Friday and pleaded not guilty.

She was granted bail and the matter is due back in court in March.

Georgie Burt, the mother of Zane, sat several seats away from Gamble during the brief court appearance.

“Our kids are dead because of you, you heartless bitch,” Ms Burt said before leaving the courtroom.

It is alleged the castle was tethered at four of its eight anchorage points.

It is also alleged pegs were not installed at the recommended 45-degree angle and pegs recommended by the manufacturer, or a suitable alternative, weren’t used.

According to court documents, seven students were on the castle when a “significant” weather event occurred, causing it to become dislodged and airborne.

They fell from the castle, while a blower attached to the castle to keep it inflated struck a nearby student.

It is alleged Gamble failed to ensure the anchorage system was sufficient to prevent the castle from lifting and failed to ensure there was a peg at each anchor point in line with the manufacturer’s instructions.

Gamble arrived at the school with two workers and set up the castle and zorb balls.

She’s accused of failing to provide the workers with information including the manufacturer’s operating manual for the castle.

It is also alleged children were exposed to a risk of serious injury or death.

– AAP